<?php

/**
 * Zend Framework
 * LICENSE
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 * @category Zend
 * @package Zend
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 * @version $Id: Exception.php 24593 2012-01-05 20:35:02Z matthew $
 */
/**
 *
 * @category Zend
 * @package Zend
 * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com)
 * @license http://framework.zend.com/license/new-bsd New BSD License
 */
class Zend_Exception extends Exception {

    /**
     *
     * @var null Exception
     */
    private $_previous = null;

    /**
     * Construct the exception
     * @param string $msg
     * @param int $code
     * @param Exception $previous
     * @return void
     */
    public function __construct ($msg = '', $code = 0, Exception $previous = null) {
        if (version_compare (PHP_VERSION, '5.3.0', '<')) {
            parent::__construct ($msg, (int) $code);
            $this -> _previous = $previous;
        } else {
            parent::__construct ($msg, (int) $code, $previous);
        }
    }

    /**
     * Overloading
     * For PHP < 5.3.0, provides access to the getPrevious() method.
     * @param string $method
     * @param array $args
     * @return mixed
     */
    public function __call ($method, array $args) {
        if ('getprevious' == strtolower ($method)) {
            return $this -> _getPrevious ();
        }
        return null;
    }

    /**
     * String representation of the exception
     * @return string
     */
    public function __toString () {
        if (version_compare (PHP_VERSION, '5.3.0', '<')) {
            if (null !== ($e = $this -> getPrevious ())) {
                return $e -> __toString () . "\n\nNext " . parent::__toString ();
            }
        }
        return parent::__toString ();
    }

    /**
     * Returns previous Exception
     * @return Exception null
     */
    protected function _getPrevious () {
        return $this -> _previous;
    }

}
